Benzocaine

Organic Chemistry Preparation of methyl Orange end In this experiment the azo dye methyl orange is prepa red-faced by the diazo mating reation. Introduction The runner step is called diazotization. The first product obtained from the coupling is the bright red irate for of methyl organge, called helianthin. In base, helianthin is born-again to the orange atomic number 11 salt, called methyl organge (1). Reaction Scheme [pic] Although sulfanilic social disease is indissoluble in acid solutions, it is nevertheless necessary to carry erupt the diazotization chemical fight downion in an acid (HNO2) solution. This problem can be avoided by precipitating sulfanilic acid from a solution in which it is initially soluble. The precipitate is a fine suspension and reacts like a shot with nitrous acid. The first step is to dissolve sulfanillic acid in primary solution. When the solution is acidified during diazotization to form nitrous acid, the sulfanilic acid is precipitated tabu of solution as a finely shared out solid, which is right away diazotized. The finely divided diazonium salt is allowed to react immediately with dimethlaniline in the solution in which it was precipitated. Mechanism diazotization: [pic] Diazo Coupling: Methyl orange is often used as an acid-base indication. In solutions that are to a greater extent basic than pH 4.

4, methyl orange exists almost alto flit forher as the yellow negative ion. In solutions that are more(prenominal) acrid than pH 3.2, it is protonated to form a red dipolar ion. Thus, methyl orange can be used as an indicator for titrations that have end point in the pH 3.2- 4.4 region. The in dicator is usually prepated as a0.01% soluti! on in water. In high concentrations in basic solution, of course, methyl orange appears orange. Acid-Base forefinger Properties of Methyl Orange [pic] Procedure Pretreatment before Diazotization 1. Dissolve 1.2 g anhydrous Na2CO3 with 50 ml DI H2O in a 125-ml Erlenmeyer flask using a stir bar. 2. Add 3.6 g anhydrous sulfanilic acid, and...If you want to get a full essay, order it on our website: OrderEssay.net

If you want to get a full information about our service, visit our page: write my essay